Norris, Montana has a Humid Continental Mild Summer, Wet All Year climate (Köppen classification: Dfb). Average annual temperatures range from -0.8 °C (low) to 14.2 °C (high). Annual precipitation averages 417.6 Millimeters. Norris is located in USDA Plant Hardiness Zone 5b. The growing season typically runs from the last frost around May 1 - May 10 through the first frost around Sep. 21 - Sep. 30.
| Month | Avg. Low | Avg. High | Avg. Precip |
|---|---|---|---|
| January | -9.3 °C | 2 °C | 12.7 mm |
| February | -8.7 °C | 3.6 °C | 13.21 mm |
| March | -5 °C | 8.3 °C | 27.43 mm |
| April | -1.4 °C | 12.7 °C | 54.1 mm |
| May | 2.7 °C | 17.8 °C | 69.6 mm |
| June | 6.3 °C | 22.7 °C | 76.45 mm |
| July | 9.2 °C | 28.8 °C | 28.96 mm |
| August | 8.2 °C | 28.6 °C | 25.91 mm |
| September | 4.4 °C | 22.9 °C | 33.02 mm |
| October | -0.5 °C | 14.8 °C | 42.67 mm |
| November | -5.4 °C | 6.7 °C | 22.1 mm |
| December | -9.7 °C | 1.7 °C | 11.43 mm |
| Annual | -0.8 °C | 14.2 °C | 417.58 mm |
| Average First Frost Date | Sep. 21 - Sep. 30 |
| Average Last Frost Date | May 1 - May 10 |
| Average Days With Frost | 125-150 Days |
| Plant Hardiness Zone | Zone 5b : -26.1°C to -23.3°C |
| Plant Hardiness Zone - 2012 | Zone 5a : -28.9°C to -26.1°C |
| Current Drought Conditions | Severe Drought |
| Köppen Climate Classification | Dfb - Humid Continental Mild Summer, Wet All Year |